Wellbore condition monitoring sensors

ABSTRACT

Disclosed is an apparatus for estimating a downhole property of interest. The apparatus includes a carrier configured to be conveyed in a borehole penetrating an earth formation and carry a releasable sensor. The sensor is configured to be released by the carrier into drilling fluid and to sense the property. The sensor includes a memory to store sensed property data. The data can be downloaded from the memory wirelessly with the sensor in the drilling fluid or by retrieving the sensor from the drilling fluid.

BACKGROUND

In wellbore operations, the condition of a wellbore, a downhole tool, a reservoir, or fluid in the wellbore is typically measured by sensors in proximity to the drill bit and transmitted to the surface of the earth by a downhole telemetry system. Alternatively, the condition information is stored in memory disposed in a downhole tool and accessed by downloading the data upon retrieval of the tool from the wellbore. While a downhole telemetry system can transmit sensor data generally continuously, the overall transmission of data may be slow due to limited bandwidth. Similarly, while downloading data from a retrieved downhole tool may be performed with high bandwidth transmission, it can take from a few hours to days in order to retrieve the tool. Both methods may be ultimately too slow when downhole conditions are rapidly changing. Hence, it would be appreciated in the drilling industry if data obtained from downhole sensors could be provided to drilling operators in a timely manner.

BRIEF SUMMARY

Disclosed is an apparatus for estimating a downhole property of interest. The apparatus includes a carrier configured to be conveyed in a borehole penetrating an earth formation and carry a releasable sensor. The sensor is configured to be released by the carrier into drilling fluid and to sense the property. The sensor includes a memory to store sensed property data.

Also disclosed is a method for estimating a downhole property of interest. The method includes: conveying a carrier through a borehole penetrating the earth; releasing a sensor into drilling fluid; sensing the property of interest using the sensor; and downloading data sensed by the sensor at a location uphole from the sensing.

BRIEF DESCRIPTION OF THE DRAWINGS

The following descriptions should not be considered limiting in any way. With reference to the accompanying drawings, like elements are numbered alike:

FIG. 1 illustrates an exemplary embodiment of a downhole tool having a plurality of releasable sensors disposed in a borehole penetrating the earth;

FIG. 2 depicts aspects of a sensor release mechanism for releasing sensors from the downhole tool into the borehole;

FIG. 3 depicts aspects of one embodiment of a sensor for measuring temperature;

FIG. 4 depicts aspects of one embodiment of a sensing element having a flexural mechanical resonator for characterizing a downhole fluid;

FIG. 5 depicts aspects of one embodiment of a sensing element using photons for sensing a downhole property of interest;

FIG. 6 depicts aspects of one embodiment of a sensing element using acoustic signals for sensing a downhole property of interest; and

FIG. 7 presents one example of a method for estimating a downhole property of interest.

DETAILED DESCRIPTION

A detailed description of one or more embodiments of the disclosed apparatus and method presented herein by way of exemplification and not limitation with reference to the Figures.

FIG. 1 illustrates an exemplary embodiment of a drill string 5 disposed in a borehole 2 penetrating the earth 3, which includes a formation 4. The formation 4 represents any downhole material of interest. A drill string rotation system 12 disposed at a drill rig 11 at the surface of the earth 3 is configured to rotate the drill string 5 in order to rotate a drill bit 6 disposed at a distal end of the drill string 5. The drill bit 6 represents any cutting device configured to cut through the earth 3 or rock in the formation 4 in order to drill the borehole 2. Disposed adjacent to the drill bit 6 is a bottom hole assembly (BHA) 7. The drill bit 6 can be included in the BHA 7 or it can be separate from it. The BHA 7 can include downhole components such as a downhole tool 10 and a mud motor (not shown). In order to cool and lubricate the drill bit 6 and flush cuttings from the borehole 2, drilling fluid 8 is pumped downhole through the interior of the drill string 5 from which it exits the drill bit 6. The drilling fluid 8 then returns to the drill rig 11 via an annulus 13 surrounding the BHA 7 and the drill string 5 within the borehole 2.

Still referring to FIG. 1, a plurality of sensors 9 is disposed at the downhole tool 10. Each of the sensors 9 is configured to sense (i.e., measure) a property of interest. The downhole tool 10 is configured to release one or more of the sensors 9 into the annulus 13 by one of two pathways. In a first pathway, one or more of the sensors 9 is released external to the downhole tool 10 and BHA 7 into the annulus 13. In a second pathway, one or more of the sensors 9 is released internal to the downhole tool 10 and BHA 7 into an internal conduit 14 conveying the drilling fluid 13 to the drill bit 6. Hence, in the second pathway, one or more of the sensors 9 is released into the annulus 13 after traversing the drill bit 6.

After a sensor 9 is released, it can perform one or more measurements of a property of interest. Non-limiting examples of the property of interest include temperature, pressure, density, viscosity, compressibility, acoustic property, magnetic property, chemical composition and material characteristic of the formation, fluid in the formation, drill string components, and drilling fluid. Applications using the sensed property of interest include detection of corrosion, scaling, asphaltenes and waxes. The property of interest can be an ambient condition (e.g., temperature or pressure) experienced by the sensor 9 or a characteristic of a downhole material such as the formation or formation fluid at the borehole 2. Measurement data is generally stored in a memory in the sensor 9.

Sensors 9 that are released travel uphole (i.e., up the borehole from the downhole tool 10 towards the surface of the earth) in the annulus 13 towards the surface of the earth 3. In one or more embodiments, the sensors 9 are buoyant in the drilling fluid 13 and thus are able to float in the drilling fluid 13 to the surface of the earth 3. Alternatively, or in addition to buoyancy, the sensor 9 may also contain a mechanism to power the sensor 9 to the surface. Non-limiting embodiments of the mechanism include piezo-actuated flappers, tails, or propellers powered by battery or energy harvesters, which in one or more embodiments can harvest energy from the drilling fluid flow, vibration, or temperature differentials.

In one or more embodiments, upon reaching the surface of the earth 3, the released sensors 9 are retrieved from the drilling fluid 13 by a receiving device such as a sieve or screen 15. After a released sensor 9 is retrieved, the stored measurement data can be downloaded from the sensor 9 either at the well site or offsite in a laboratory.

In one or more embodiments, the stored measurement data from a released sensor 9 is received by the receiving device as radio frequency (RF) energy via a receiver 16 and a hoop antenna 17 at the surface while the sensor 9 is still immersed in the drilling fluid 8. Alternatively, or in combination, the receiver 16 can represent a receiver and a transducer configured to receive magnetic, acoustic or optical signals.

In one or more embodiments, the sensors 9 can be interrogated and then reset to store multiple layers of information through different runs where they can run or circulate continuously with the drilling fluid without being filtered out of the drilling fluid. As circulating sensors, these sensors 9 can act as drilling fluid monitors, monitoring properties of the drilling fluid throughout a drilling run.

Reference may now be had to FIG. 2 depicting aspects of a sensor release mechanism 20 configured to release one or more of sensors 9 from the downhole tool 10. The sensor release mechanism 20 includes a rack 21 for holding and securing the plurality of sensors 9 in the downhole tool 10. The sensor release mechanism 20 also includes an ejector 22 coupled to a controller 23 and configured to eject each of sensors 9 from the downhole tool 10. A detachable connector 24 couples each of the sensors 9 to the controller 23, which can issue download information to each of the sensors 9. The downloaded information can include commands to activate each sensor 9 to commence performing measurements upon ejection or after a time delay. The download information can also include other information such as the present time and/or depth when each sensor 9 is released. It can be appreciated that the controller 23 can also be configured to download measurement data from other downhole tools disposed at the BHA 7 to a memory in one or more of the sensors 9. It can be appreciated that the downloading of measurement data from other downhole tools to the sensors 9 can provide a redundant method of transmitting data from the other downhole tools to the surface of the earth. Similarly, it can be appreciated that multiple sensors 9 having the same information can provide redundancy in the system such that missing or damaged sensors 9 will not cause a loss of data.

Still referring to FIG. 2, the controller 23 is coupled to door actuators 25 and 26 and configured to operate doors 27 and 28, respectively. The doors 27 and 28 are configured to allow the drilling fluid 8 to enter and exit the downhole tool 10 in order to provide the first pathway leading to the annulus 13. It can be appreciated that the doors 27 and 28 can be hinged doors, sliding doors or a combination thereof appropriate for downhole use. Alternatively, another door or doors in addition to or instead of the doors 27 and 28 may be configured to provide access to the internal conduit 14.

Reference may now be had to FIG. 3 depicting aspects of one sensor 9 in the plurality of sensors 9. The sensor 9 includes a sensing element 30 coupled to a processing unit 31, both disposed on substrate 32, which can include connections between various components. The sensing element 30 is configured to interact with the property of interest being sensed. In the embodiment of FIG. 3, the sensing element 30 is a thermocouple 33 configured to sense temperature. The processing unit 31 is configured to process signals received from the sensing element 30 in order to measure the property of interest and store sensed measurement data for later retrieval. The processing unit 31 can include a clock configured to provide a time at which each measurement is performed by the sensor 9. The processing unit 31 includes memory 34 for storing the sensed measurement data and a download interface 35 for downloading the stored sensed measurement data. In non-limiting embodiments, the memory 34 can be a rewritable memory or a one-time set memory. In one or more embodiments, the download interface 35 includes a connector 36. The connector 36 can also be used as a power receptacle to receive power from the downhole tool 10 such as for recharging a power source. In one or more embodiments, the download interface 35 includes a transmitter 37 coupled to an antenna 38 for transmitting the stored sensed measurement data to the receiver 16 via the antenna 17. In one or more embodiments, the transmitter 37 in the download interface 35 can represent a transceiver and transducer configured transmit or receive radio frequency (RF), acoustic, or magnetic signals for data or power transfer. A power source 45 is disposed on the substrate 32 and is configured to supply electrical power to the processing unit 31 and/or the sensing element 30. The power source 45 can include batteries (disposable or rechargeable), supercapacitors, or energy harvesting mechanisms that can harvest energy from drilling fluid flow, vibrations, or temperature differentials besides other processes. A buoyancy device 39 if needed is coupled to the substrate 32 in order to insure that the sensor 9 floats in the drilling fluid 8. In one or more embodiments, components of the sensor 9 are integrated into one or more integrated circuits. In one or more embodiments, the sensor 9 is built as a micro-electromechanical system (MEMS) or nano-electromechanical system (NEMS) in order for the sensor 9 to be small enough to travel unimpeded in the drilling fluid 8.

Still referring to FIG. 3, the sensor 9 can include a signal-emitting beacon 43 configured to act as a transmitter to engage the sieve or screen 15 or capture mechanism such as an electromagnetic trap. The beacon 43 can be used by the capture mechanism or trap at the surface to locate the sensor 9, engage the trap, recover the sensor 9 and then release the trap. A moving or varying beacon 43 can signal a still uncaptured sensor 9 while a static signal strength can signal that a sensor 9 is captured in the trap.

Reference may now be had to FIG. 4 depicting aspects of another embodiment of the sensing element 30. In the embodiment of FIG. 4, the sensing element 30 includes a plurality of flexural mechanical resonators 40 configured to be immersed in a liquid of interest in order to sense a physical property such as density or viscosity of the liquid of interest. In one or more embodiments, each flexural mechanical resonator 40 is made of a piezoelectric material embedded with one or more electrodes. An electric field applied by the one or more electrodes causes the piezoelectric material to resonate in the liquid of interest. The resonating or motion of the resonator in the liquid of interest provides an electrical impedance (also called fluid motion impedance) as measured via the one or more electrodes that is related to a physical property of the liquid of interest. Each flexural mechanical resonator 40 in the plurality is configured to measure a physical property in a selected range of values such that the plurality of flexural mechanical resonators 40 can measure that physical property over a wide range of values that encompasses the selected ranges of values. Alternatively, each flexural mechanical resonator 40 can be tuned to detect a specific chemical(s) or a property of that chemical(s).

Reference may now be had to FIG. 5 depicting aspects of another embodiment of the sensing element 31. In the embodiment of FIG. 5, the sensing element 30 includes a light source 50 and a photodetector 51. The light source 50 is configured to generate or emit light onto a material of interest such as a wall of the borehole 2. The light detector 51 is configured to detect the emitted light that is reflected from the material of interest in order to sense or measure a property of the material of interest. Alternatively, the photodetector 51 can be configured to detect light traversing the material of interest in order to sense or measure the property. It can be appreciated that in one or more embodiments the sensing element 31 depicted in FIG. 5 can be configured for reflective or transmissive spectroscopy.

Reference may now be had to FIG. 6 depicting aspects of another embodiment of the sensing element 30. In the embodiment of FIG. 6, the sensing element includes one or more acoustic transducers 60. Each acoustic transducer 60 is configured to transmit and/or receive acoustic energy or signals. The acoustic signals can propagate through or reflect from the drilling fluid, the formation, formation fluid, and/or the BHA in order to characterize those entities.

It can be appreciated that the sensors 9 can be used to detect a condition of the drill bit 6 when the sensors 9 are released into the internal conduit 14. In one or more non-limiting embodiments, the sensors 9 can be used to detect a condition or property of the drilling fluid 8, formation fluid disposed in the borehole 2, the formation 4 at a wall of the borehole 2, or the BHA 7. It can be appreciated that the use the plurality of sensors 9 provides for multiple measurements of the same property of interest, which can be combined or averaged to provide a measurement having increased accuracy or precision versus a single measurement by a single sensor 9. In addition, measurements obtained by the sensors 9 can be stacked over a period of time.

It can be appreciated that hundreds of the sensors 9 can be fabricated at low cost using semiconductor fabrication technology and that hundreds of the sensors 9 may be deployed during a drilling operation where the downhole tool 10 is not removed from the borehole 2. It can be appreciated that when a plurality of the sensors 9 is released into the borehole 2, the sensors 9 can be configured to be self-actuating upon detection of the drilling fluid 8 electrically or optically as non-limiting examples.

It can be appreciated that the sensor 9 can be made on silicon, glass, ceramic, metal, polymer, plastic and other substrates using conventional and semiconductor processing/fabrication methods not limited to CMOS batch fabrication, ink printing, screen printing, embossing and other methods known in the art. In one or more embodiments, the sensor 9 can be built on a tape such as a polyimide tape. In one or more embodiments, the sensor 9 can be encapsulated in hard abrasion resistant materials such as ceramics and/or in hard high temperature capable polymers such as PEEK to avoid physical damage to sensor components.

FIG. 7 presents one example of a method 70 for estimating a downhole property of interest. The method 70 calls for (step 71) conveying a carrier through a borehole penetrating the earth. Further, the method 70 calls for (step 72) releasing a sensor from the carrier into drilling fluid in the borehole. One or more sensors 9 can be released while the BHA is being inserted into the borehole, during drilling, or while the drill stem is static in the borehole. Further, the method 70 calls for (step 73) sensing the property of interest using the sensor. The sensed property measurement(s) can be stored in a memory for later downloading. Further, the method 70 calls for (step 74) downloading data from the sensor at a location uphole from the sensing.

In support of the teachings herein, various analysis components may be used, including a digital and/or an analog system. For example, the downhole electronics 11, the surface computer processing 12, or the processing unit 31 may include the digital and/or analog system. The system may have components such as a processor, storage media, memory, input, output, communications link (wired, wireless, pulsed mud, optical or other), user interfaces, software programs, signal processors (digital or analog) and other such components (such as resistors, capacitors, inductors and others) to provide for operation and analyses of the apparatus and methods disclosed herein in any of several manners well-appreciated in the art. It is considered that these teachings may be, but need not be, implemented in conjunction with a set of computer executable instructions stored on a non-transitory computer readable medium, including memory (ROMs, RAMs), optical (CD-ROMs), or magnetic (disks, hard drives), or any other type that when executed causes a computer to implement the method of the present invention. These instructions may provide for equipment operation, control, data collection and analysis and other functions deemed relevant by a system designer, owner, user or other such personnel, in addition to the functions described in this disclosure.

Further, various other components may be included and called upon for providing for aspects of the teachings herein. For example, a power supply (e.g., at least one of a generator, a remote supply and a battery), cooling component, heating component, magnet, electromagnet, sensor, electrode, transmitter, receiver, transceiver, antenna, controller, optical unit, electrical unit or electromechanical unit may be included in support of the various aspects discussed herein or in support of other functions beyond this disclosure.

The term “carrier” as used herein means any device, device component, combination of devices, media and/or member that may be used to convey, house, support or otherwise facilitate the use of another device, device component, combination of devices, media and/or member. Other exemplary non-limiting carriers include drill strings of the coiled tube type, of the jointed pipe type and any combination or portion thereof. Other carrier examples include casing pipes, wirelines, wireline sondes, slickline sondes, drop shots, bottom-hole-assemblies, drill string inserts, modules, internal housings and substrate portions thereof.

Elements of the embodiments have been introduced with either the articles “a” or “an.” The articles are intended to mean that there are one or more of the elements. The terms “including” and “having” are intended to be inclusive such that there may be additional elements other than the elements listed. The conjunction “or” when used with a list of at least two terms is intended to mean any term or combination of terms. The terms “first” and “second” are used to distinguish elements and are not used to denote a particular order. The term “couple” relates to coupling a first component to a second component either directly or indirectly through an intermediate component.

It will be recognized that the various components or technologies may provide certain necessary or beneficial functionality or features. Accordingly, these functions and features as may be needed in support of the appended claims and variations thereof, are recognized as being inherently included as a part of the teachings herein and a part of the invention disclosed.

While the invention has been described with reference to exemplary embodiments, it will be understood that various changes may be made and equivalents may be substituted for elements thereof without departing from the scope of the invention. In addition, many modifications will be appreciated to adapt a particular instrument, situation or material to the teachings of the invention without departing from the essential scope thereof. Therefore, it is intended that the invention not be limited to the particular embodiment disclosed as the best mode contemplated for carrying out this invention, but that the invention will include all embodiments falling within the scope of the appended claims. 

What is claimed is:
 1. An apparatus for estimating a downhole property of interest, the apparatus comprising: a carrier configured to be conveyed in a borehole penetrating an earth formation and carry a releasable sensor; and a sensor configured to be released by the carrier into drilling fluid and to sense the property; wherein the sensor comprises a memory to store sensed property data.
 2. The apparatus according to claim 1, wherein the carrier is configured to release the sensor external to the carrier and into the borehole where the sensor travels uphole in the drilling fluid.
 3. The apparatus according to claim 1, where the carrier is configured to release the sensor internal to the carrier where the sensor exits a drill bit into the borehole where the sensor travels uphole in the drilling fluid.
 4. The apparatus according to claim 1, further comprising a receiving device configured to receive the sensor from the borehole fluid or the sensed memory data from the sensor that has been released from the carrier.
 5. The apparatus according to claim 4, wherein the receiving device comprises a screen configured to entrap the sensor.
 6. The apparatus according to claim 4, wherein the receiving device comprises a magnet configured to attract the sensor in the borehole fluid.
 7. The apparatus according to claim 4, wherein the receiving device comprises a first transducer configured to receive signals from the sensor.
 8. The apparatus according to claim 7, wherein the first transducer comprises an antenna and the signals are electromagnetic signal.
 9. The apparatus according to claim 7, wherein the sensor further comprises a second transducer configured to transmit the signals to the receiving device in order to transmit the sensed property data.
 10. The apparatus according to claim 9, wherein the second transducer comprises an antenna and the signals are electromagnetic signals.
 11. The apparatus according to claim 9, wherein the sensor further comprises a transmitter configured to transmit the sensed property data using the second transducer.
 12. The apparatus according to claim 9, wherein the second transducer is configured to transmit acoustic, magnetic or optical signals.
 13. The apparatus according to claim 4, the sensor comprising a connector configured to receive data from the carrier or download data to the receiving device.
 14. The apparatus according to claim 4, wherein the sensor comprises a beacon configured to emit a signal to activate or deactivate the receiving device.
 15. The apparatus according to claim 1, wherein the sensor is encapsulated in a protective coating.
 16. The apparatus according to claim 1, wherein the sensor comprises a thermocouple configured to measure temperature.
 17. The apparatus according to claim 1, wherein the sensor comprises a flexural mechanical resonator configured to measure a property of a downhole fluid.
 18. The apparatus according to claim 17, wherein the flexural mechanical resonator comprises a plurality of flexural mechanical resonators with each resonator tuned to a specific range of measurements.
 19. The apparatus according to claim 1, wherein the sensor comprises a processor configured to operate the sensor to obtain the sensed property data and to store the sensed property data in the memory.
 20. The apparatus according to claim 19, wherein the processor comprises a clock configured to provide a time at which each measurement is performed.
 21. The apparatus according to claim 1, wherein the sensor comprises a power source configured to power the sensor.
 22. The apparatus according to claim 1, wherein the sensor comprises a pressure transducer configured to measure depth in the borehole at which each measurement is performed.
 23. The apparatus according to claim 1, wherein the sensor is configured to sense at least one of temperature, pressure, density, viscosity, compressibility, acoustic property, magnetic property, chemical composition and material characteristic of the formation, fluid in the formation, drill string components, and drilling fluid.
 24. The apparatus according to claim 1, wherein the carrier is conveyed by a drill string or coiled tubing.
 25. A method for estimating a downhole property of interest, the method comprising: conveying a carrier through a borehole penetrating the earth; releasing a sensor into drilling fluid; sensing the property of interest using the sensor; and downloading data sensed by the sensor at a location uphole from the sensing.
 26. The method according to claim 25, wherein downloading comprises retrieving the sensor from the drilling fluid or receiving transmitted sensed data from the sensor.
 27. The method according to claim 25, wherein the sensing is performed before the releasing.
 28. The method according to claim 25, wherein the sensor comprises a plurality of sensors.
 29. The method according to claim 28, wherein two or more sensors in the plurality are configured to sense a same property. 